1. Field of the Invention
The present invention relates to an automatic composition apparatus and method for automatically composing a piece of music according to various conditions relating to music, and a storage medium that stores a program to be executed for automatically composing a piece of music.
2. Prior Art
A known automatic composition apparatus for automatically composing a piece of music according to various conditions relating to music is disclosed in, for example, laid-open Japanese Patent Publication (Kokai) No. 9-50278 and corresponding U.S. Pat. No. 5,736,663.
The automatic composition apparatus disclosed in the above-identified publication or U.S. patent is adapted to analyze and extract musical features of an already-composed piece of music, and store the results of the analyzing and extracting process as a music template into a performance data memory. The known apparatus enables the user to suitably modify a music template selected from various music templates stored in the memory, to thereby automatically compose a piece of music based on the template that has been modified.
The data contained in the music template includes those related to pitches of each phrase, including "pitch pattern of phrase", "first to last tones of phrase", and so forth. Based on these data, a pitch corresponding to each syllable in the phrase in question is determined. More specifically, where selected ones of the degrees (I, II, III, IV, V, VI, VII) are set for the "first to last tones of phrase", the pitches of the first and last syllables of the phrase in question are determined based on the set degrees. Where no degree is set for the "first to last tones of phrase", the pitches of the first and last syllables of the phrase in question are determined based on "emotional fluctuations" contained in the music template. Where a pitch pattern is set as the "pitch pattern of phrase" for the phrase in question, the pitches of syllables other than the first and last syllables of the phrase are determined based on this pitch pattern. Where no pitch pattern is set as the "pitch pattern of phrase" for the phrase in question, on the other hand, a pitch pattern that is approximate to a graphic pattern representing the "emotional fluctuation" is selected, and the pitches of the syllables are determined based on the selected pitch pattern. Once a melody is generated in this manner, the user judges whether there is any problem or disadvantage in the melody, by actually listening to the piece of music, and manually modifies the melody if there is any problem.
In another known automatic composition apparatus as disclosed in Japanese Patent Publication (Kokoku) No. 60-40027 and corresponding U.S. Pat. No. 4,399,731, pitches that are selected at random are examined in terms of certain musical conditions, and adopted to provide a melody of the music if they meet the musical conditions. If the selected pitches do not meet the musical conditions, pitches are selected at random again, to generate a melody.
In the former known automatic composition apparatuses as described above, a melody can be generated according to data contained in the music template, namely, data related to pitches for each phrase, but the resulting melody thus generated may be unfavorable in a musical sense or may not satisfy any musical requirement. If such a melody is generated, the user needs to manually modify the melody, which requires a cumbersome procedure.
In the latter known automatic composition apparatus, the randomly selected pitches are examined in terms of certain musical conditions, and only the pitches that meet the conditions are adopted or actually used in the piece of music. However, melodies generated in this manner are not always favorable in a musical sense, namely, do not always satisfy musical requirements. Namely, new pitches are determined only in view of the previous pitch and current pitch, and therefore musically unfavorable or undesirable pitches may be selected due to a failure to take account of the next pitch.